first off, yes I do have nostalgia with this game. However I just recently played through this game and I stand by my score of 8/10. I think im one of the select few people who actually really enjoy the Knuckles/Rouge stages (except Meteor herd). The egg-man/Tails sections are kinda lame, However, the sonic/shadow stages are the best 3d stages in any 3d sonic game, and that's a fact. so many secrets in each level and unlocking the power-ups throughout the game encourages multiple replays of each level. you get a lot of freedom as well since its not just run in a straight line like all the new 3d sonic titles. ALSO, the Chao garden is waaayyyy better in this game compared to sonicA1. so many ways to customize your chao with the hero/dark path, you can sink literal days just messing around in the chao garden alone. i only wish there was more minigames and things to do once you had your chao maxed out.
not to mention that this game has a killer soundtrack as well.
Solid 8/10 dont let the haters turn you away from a very enjoyable game.